In this postdoctoral F32 Kirschstein NRSA, Dr. Kamryn Eddy proposes a comprehensive research and training plan in the study of diagnostic classification of eating disorders (EDs). Her long-term program of research goal is to establish empirically-valid diagnostic classification systems of EDs in children, adolescents, and adults, which will inform clinical research and practice. Identified problems with the current diagnostic system of EDs, including its imperfect application to clinical samples, longitudinal diagnostic instability, and difficulty in applying existing diagnostic criteria for EDs to youth, challenge the validity of the current system, thereby limiting its utility. In preparation for DSM-V, expected to be published in 2012, the classification system of EDs is being re-examined. Dr. Eddy proposes to empirically examine classification utilizing two uniquely rich clinical samples of individuals with EDs for which she has been actively involved in data collection during her early career. First, using a longitudinal dataset of treatment-seeking adult women with EDs (N=246) followed for a median of 9.5 years, the applicant will identify and externally validate ED phenotypes utilizing three advanced statistical approaches (latent profile analysis, taxometric analysis, and latent transition analysis). Second, using a clinical sample of adolescents (ages 12-19) with EDs (N=300), the applicant will identify and externally validate ED phenotypes using two advanced statistical approaches (latent profile analysis, taxometric analysis). In collaboration with two sponsors who are each experts in the study of EDs and a team of expert consultants, the applicant has developed a comprehensive training plan that will prepare her with a requisite skill set for a research career in the nosology of EDs achieved through four objectives including, (1) to advance her statistical and data-analytic skills with a focus on developing skills that can be used in nosological research, (2) to increase her understanding of conceptual and methodological issues in nosological research, (3) to develop a familiarity with biological approaches to validating nosological schemas, and (4) to improve her grant writing skills leading to the submission of a K application. PUBLIC HEALTH RELEVANCE: EDs are a significant problem most often observed in adolescent and young adult females and associated with substantial medical morbidity, psychiatric comorbidity, increased mortality, and high treatment costs. Classification research is relevant and timely in preparation for DSM-V and may facilitate etiological, prevention, and intervention EDs research. The data sets available to the applicant are unique in the field of EDs and provide significant opportunities to explore the validity of the ED diagnoses. The proposed research will empirically derive and characterize ED phenotypes, and the corresponding training plan will provide the applicant with the statistical, conceptual, and methodological foundation necessary to advance her program of research.